How Bullying May Affect Teenagers’ Brains

A study conducted by Quinlan et al. (2018) on the effects of bullying on the brain and involving the study of 682 teenagers required these young people to fill out questionnaires about the extent to which they experienced bullying. The study ran over a number of years (i.e. it was a longitudinal study) and each of the 682 participants completed the questionnaires at the ages of 14, 16 and 19 years so that it could be ascertained how much bullying each had experienced over a 5 year period.

In order to investigate the effects of bullying on their brains, each of the 682 participants underwent brain scans (MRIs) at the ages of 14 and 19.


The results of the study found that being severely and chronically bullied can have the following effects of the brain :

Reduced size of left putaman

Reduced size of left caudate


Quinlan, the leading researcher of the study, suggests that one effect of the above abnormalities is to increase the affected individuals’ level of generalized anxiety.


Whilst Quinlan did not elucidate the biological mechanisms involved that were causing these effects, it is already known, from other research, that severe, ongoing stress (sometimes referred to as ‘toxic stress’) can cause the body to produce too much of the stress hormone known as cortisol and it is this excess that can damage the brain in various ways such as disrupting synapse regulation, brain cell death and, of crucial relevance to Quinlan’s study, reduction in the size of the brain.


Quinlan states that, due to the brain’s plasticity, the above abnormalities might be reversible although this matter will need to be investigated further in future research. 


Previous studies have shown that the brain’s anterior cingulate cortex is also adversely affected by chronic bullying; interestingly, this part of the brain seems to be involved in the generation of both psychological and physical pain which perhaps helps explain why when we experience emotional damage it can manifest itself by giving rise to sensations of pain which feel as if they have a physical component.

Experiencing chronic, severe bullying has also be found to be correlated with: depression, anxiety, complex PTSD, alcoholism, drug abuse, impaired academic performance and suicidal ideation.


Erin Burke Quinlan et al. (2018). Peer victimization and its impact on adolescent brain development and psychopathology. Molecular Psychiatry, 2018; DOI: 10.1038/s41380-018-0297-9

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David Hosier BSc Hons; MSc; PGDE(FAHE).

About David Hosier BSc Hons; MSc; PGDE(FAHE)

David Hosier MSc holds two degrees (BSc Hons and MSc) and a post-graduate diploma in education (all three qualifications are in psychology). He also holds UK QTS (Qualified Teacher Status). He has worked as a teacher, lecturer and researcher. His own experiences of severe childhood trauma and its emotional fallout motivated him to set up this website,, for which he exclusively writes articles. He has published several books including The Link Between Childhood Trauma And Borderline Personality Disorder, The Link Between Childhood Trauma ANd Complex Posttraumatic Stress Disorder and  How Childhood Trauma Can Damage The Developing Brain (And How These Effects Can Be Reversed). He was educated at the University of London, Goldsmith’s College where he developed his interest in childhood experiences leading to psychopathology and wrote his thesis on the effects of childhood depression on academic performance. This site has been created for educational purposes only.

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